1. Field of the Invention
The present invention relates to a complex circuit board comprising an electrode clasped between a dielectric substrate and a magnetic substrate, a nonreciprocal circuit device, a resonator, a filter, a duplexer, a communications device, a circuit module, a method for manufacturing the complex circuit board, and a method for manufacturing the nonreciprocal circuit device.
2. Description of the Related Art
Conventionally, dielectric substrates or magnetic substrates having electrode patterns thereon, forming a capacitance element and/or an inductance element, for example, have been laminated in multiple stages to form a resonator circuit or the like. Depending on the application and desired characteristics and the like, low-profiling is sometimes required, and a conventional complex circuit board has been devised to satisfy such requirements.
A conventional complex circuit board will be explained based on FIGS. 23 and 24. FIG. 23 is a plan view of a conventional complex circuit board, and FIG. 24 is a cross-sectional view taken along the line Wxe2x80x94W of FIG. 23.
As shown in FIGS. 23 and 24, the conventional complex circuit board 110 comprises a dielectric substrate 111, a magnetic substrate 112, and an electrode pattern 120 clasped therebetween. The electrode pattern 120 comprises a capacitance element 121, an inductance element 122, a transmission line 123, and the like, and ground electrodes 113 are provided on the outer faces of the dielectric substrate 111 and the magnetic substrate 112. The complex circuit board 110 of this constitution functions here as a low-pass filter.
In the conventional complex circuit board 110, the electrode pattern 120 is provided by using plating or the like to form electrodes 120a and 120b facing each other on the dielectric substrate 111 and the magnetic substrate 112, respectively, and by providing a connection electrode 120c thereabove. The electrode pattern 120 is completed by affixing together the electrodes 120a and 120b respectively provided on the dielectric substrate 111 and the magnetic substrate 112, with the connection electrode 120c therebetween.
The characteristics of the capacitance element, the inductance element, resistors, transmission lines, and the like, which are provided on the complex circuit board, alter according to their positional relationships to the dielectric substrate and the magnetic substrate. For instance, the inductance element achieves a greater inductance when it is near to the magnetic substrate. Moreover, when the inductance element is near to the magnetic substrate, it can be miniaturized while obtaining the same inductance. Similarly, the capacitance element achieves a greater capacitance when it is near to the dielectric substrate, and it can be miniaturized while still obtaining the same capacitance.
However, in the conventional complex circuit board, since the electrode pattern clasped between the dielectric substrate and the magnetic substrate is formed by affixing together electrodes provided on the dielectric substrate and the magnetic substrate, the entire electrode pattern lies within a single plane. That is, the capacitance element, the inductance element, the resistors, the transmission lines, and the like are disposed all at an equal distance from the dielectric substrate and from the magnetic substrate.
Furthermore, although the inductance element obtains a larger inductance when it is provided nearer to the magnetic substrate, its inductance is lowered when a dielectric substrate is nearby, because the coupling of the inductance element to the dielectric becomes stronger.
Furthermore, in the case of a distributed constant nonreciprocal circuit device, for instance, the electrode comprises a resonator portion and a transmission line portion, and the nonreciprocity of the device when a dc magnetic field is applied thereto is increased by providing the resonator portion near to the magnetic substrate. However, when a dielectric substrate is provided nearby, the coupling of the resonator portion to the dielectric is strengthened, lowering the nonreciprocity of the device.
Therefore, when the capacitance element, the inductance element, and the like formed by the electrode pattern, clasped between the dielectric substrate and the magnetic substrate, are provided within a single plane, there are disadvantages that the inductance can be increased only by a limited value, the elements cannot be miniaturized, and consequently the complex circuit board cannot be miniaturized. There is an additional disadvantage that it is not possible to precisely design the characteristics of the capacitance element, the inductance element, the resistor, the transmission lines, and the like.
The complex circuit board, nonreciprocal circuit device, resonator, filter, duplexer, communications device, circuit module, method for manufacturing the complex circuit board, and method for manufacturing the nonreciprocal circuit device of the present invention have been realized in consideration of the problems described above, and aim to solve these problems by providing a complex circuit board, a nonreciprocal circuit device, a resonator, a filter, a duplexer, a communications device, and a circuit module, which can be miniaturized and have excellent characteristics, a method for manufacturing the complex circuit board, and a method for manufacturing the nonreciprocal circuit device.
In order to achieve the above objects, the complex circuit board of the present invention comprises a dielectric substrate; a magnetic substrate, a space being provided between the magnetic substrate and the dielectric substrate; and an electrode provided between the dielectric substrate and the magnetic substrate. The electrode is relatively near to the dielectric substrate side at a predetermined position, and is relatively near to the magnetic substrate side at another position, which is different from the predetermined position.
Consequently, a desired distance can be set from the inductance element, the capacitance element, the resistor, the transmission line portion, and the like formed by the electrode pattern to the dielectric substrate or the magnetic substrate, making it possible to design the degree of coupling between these elements and the dielectric and magnetic substrates, enabling the characteristics of these elements to be precisely designed.
For instance, when ferrite is used as the magnetic substrate, it has a dielectric constant of around 10 to 15, a dielectric loss tangent of 1xc3x9710xe2x88x923 to 1xc3x9710xe2x88x924, and permeability of 1 or more. On the other hand, generally used dielectric substrates have a dielectric constant of around 10 to 100, a dielectric loss tangent of 5xc3x9710xe2x88x924 to 1xc3x9710xe2x88x925, and permeability of 1. For this reason, a greater practical dielectric constant and higher capacitance can be obtained when the capacitance element of the electrode is provided near to the dielectric substrate. Furthermore, when the electrode is near to the dielectric substrate, the same capacitance can be obtained with a smaller capacitance element. Further, a transmission line portion with low transmission loss can be obtained by providing the electrode near to a dielectric substrate having a small dielectric loss tangent. Moreover, greater practical permeability and higher inductance can be obtained when the inductance element of the electrode is provided near to the magnetic substrate. Furthermore, when the electrode is near to the magnetic substrate, the same inductance can be obtained with a smaller inductance element.
Preferably, the electrode of the complex circuit board should be very close (i.e., adjacent or in contact with) or near (i.e., spaced a predetermined distance from) the dielectric substrate side at a predetermined position, and very close or near to the magnetic substrate side at another position which is different from the predetermined position.
In some embodiments, the electrode and the corresponding substrate may optionally be separated and simultaneously adhered to each other by an adhesive layer.
With this arrangement, the coupling between the electrode and the dielectric substrate is strengthened by placing the electrode near or very close to the dielectric substrate, and the coupling between the electrode and the magnetic substrate is strengthened by placing the electrode near or very close to the magnetic substrate.
Furthermore, the complex circuit board may comprise a substance having a lower dielectric constant than the dielectric substrate. The substance of low dielectric constant is provided between the electrode near to the magnetic substrate side and the dielectric substrate.
This weakens the coupling between the electrode near to the magnetic substrate side and the dielectric substrate, ensuring that the effects of providing the electrode near to the magnetic substrate are not lost.
In another arrangement of the complex circuit board of the present invention, the electrode near to the dielectric substrate side and the electrode near to the magnetic substrate side may be joined together in a single body.
As a consequence, there is no need to connect the electrode on the dielectric substrate to the electrode on the magnetic substrate, eliminating problems of reduced reliability and time-consuming manufacturing processes which such connection causes.
In another arrangement, a substrate having electrodes on its top and bottom faces, the electrodes being connected by a through hole, may be provided between the dielectric substrate and the magnetic substrate.
This enables the complex circuit board to be made easily by affixing the dielectric substrate to the magnetic substrate with the substrate provided with electrodes clasped therebetween.
Alternatively, a capacitance element is provided to the electrode near to the dielectric substrate side, and an inductance element is provided to the electrode near to the magnetic substrate side.
Consequently, the capacitance element can be made smaller than conventional elements of the same inductance, and the inductance element can be made smaller than conventional elements of the same inductance.
With this constitution, the dielectric substrate and the magnetic substrate need only be provided at the portions where they are needed, avoiding wasteful use of the dielectric substrate and the magnetic substrate.
Furthermore, a nonreciprocal circuit device of the present invention may comprise multiple intersecting inductance element portions, a capacitance element portion connected thereto, and a magnet for applying a dc magnetic field.
Consequently, the inductance element portion of the nonreciprocal circuit device is near to the magnetic substrate, and the capacitance element portion is near to the dielectric substrate, enabling the nonreciprocal circuit device to be miniaturized.
A resonator of the present invention may comprise the complex circuit board described above, wherein the electrodes provided between the dielectric substrate and the magnetic substrate form a capacitance element and an inductance element, thereby forming a resonator.
Consequently, the resonator can be miniaturized by, for instance, providing the inductance element of the resonator near to the magnetic substrate, and providing the capacitance element near to the dielectric substrate.
Furthermore, a filter of the present invention may comprise the resonator described above, and input/output connection means.
Consequently, the filter can be miniaturized by, for instance, providing the inductance element of the filter near to the magnetic substrate, and providing the capacitance element near to the dielectric substrate.
A duplexer of the present invention may comprise at least two filters, input/output connection means connected to each of the filters, and antenna connection means connected jointly to the filters. In this case, at least one of the filters may comprise the filter of the present invention described above.
Consequently, the duplexer can be miniaturized by, for instance, providing the inductance element of the duplexer near to the magnetic substrate, and providing the capacitance element near to the dielectric substrate.
Furthermore, a communications device of the present invention may comprise the duplexer described above, a circuit for transmitting, connected to at least one input/output connection means of the duplexer, a circuit for receiving, connected to at least one input/output connection means other than the input/output connection means connected to the circuit for transmitting, and an antenna connected to the antenna connection means of the duplexer.
Consequently, the communications device can be miniaturized by, for instance, providing the inductance element of the communications device near to the magnetic substrate, and providing the capacitance element near to the dielectric substrate.
Furthermore, a circuit module of the present invention may have at least one functional element comprising the complex circuit board of the present invention described above. Consequently, the circuit module can be miniaturized by, for instance, providing the inductance element of the circuit module near to the magnetic substrate, and providing the capacitance element near to the dielectric substrate.
Furthermore, a nonreciprocal circuit device of the present invention may comprise a dielectric substrate, a magnetic substrate, a space being provided between the magnetic substrate and the dielectric substrate, an electrode provided between the dielectric substrate and the magnetic substrate, the electrode comprising a resonator portion and a transmission line portion, and a magnet for applying a dc magnetic field. The transmission line portion of the electrode is relatively near to the dielectric substrate side, and the resonator portion of the electrode is relatively near to the magnetic substrate side.
Consequently, the transmission line portion of the electrode is near to the dielectric substrate, reducing propagation loss, and enabling the device to be made smaller than conventional devices having the same characteristics. Furthermore, since the resonator portion of the electrode is near the magnetic substrate, it is more strongly coupled with the magnetic substrate, improving the nonreciprocity of the device.
Preferably, in the specific form of the invention set forth above, the transmission line portion of the electrode is very close or near to the dielectric substrate side, and the resonator portion of the electrode is very close or near to the magnetic substrate side.
Consequently, the electrode which is very close or near to the dielectric substrate side is more strongly coupled thereto, and the electrode which is very close or near to the magnetic substrate side is more strongly coupled thereto.
In yet another arrangement, a substance having a lower dielectric constant than the dielectric substrate may be provided between the dielectric substrate and the resonator portion of the electrode near to the dielectric substrate side.
Consequently, it is possible to weaken the coupling between the dielectric substrate and the electrode near to the magnetic substrate side, ensuring that the effects of providing the electrode near to the magnetic substrate are not lost.
In yet another arrangement of the nonreciprocal circuit device, a substrate having electrodes on its top and bottom faces, the electrodes being connected by a through hole, may be provided between the dielectric substrate and the magnetic substrate.
Consequently, the complex circuit board can be made easily by affixing the dielectric substrate to the magnetic substrate with the substrate provided with electrodes clasped therebetween.
Consequently, the dielectric substrate and the magnetic substrate need only be provided at the portions where they are needed, avoiding wasteful use of the dielectric substrate and the magnetic substrate.
Furthermore, a communications device of the present invention may comprise the nonreciprocal circuit device described above, a circuit for transmitting, a circuit for receiving, and an antenna.
Consequently, the transmission line portion of the nonreciprocal circuit device is near to the dielectric substrate side, and the resonator portion is near to magnetic substrate side, improving the characteristics of the communications device and enabling it to be miniaturized.
Furthermore, the present invention may provide a method for manufacturing a complex circuit board comprising the steps of providing a dielectric substrate; providing a film of low dielectric constant, comprising a substance having a lower dielectric constant than the dielectric substrate, on said dielectric substrate; providing an electrode pattern on the dielectric substrate which the film of low dielectric constant has been provided on; and affixing a magnetic substrate to the dielectric substrate on which the electrode pattern has been provided.
Consequently, the electrodes of the complex circuit board, which has an electrode pattern near to the dielectric substrate or the magnetic substrate at a predetermined position, can be provided in a single process.
Furthermore, a method for manufacturing a complex circuit board may comprise the steps of providing a dielectric substrate; providing a magnetic substrate; providing an electrode pattern on top and bottom faces of a substrate of low dielectric constant having a lower dielectric constant than the dielectric substrate; providing a through hole running between the electrode on the top face and the electrode on the bottom face; and affixing the dielectric substrate to the magnetic substrate so as to clasp the substrate of low dielectric constant therebetween.
Consequently, a complex circuit board having an electrode pattern near to the dielectric substrate or the magnetic substrate at a predetermined position can be easily manufactured by affixing the dielectric substrate to the magnetic substrate, with the substrate provided with electrodes clasped therebetween.
Yet another method for manufacturing a complex circuit board may comprise the steps of providing a dielectric substrate; providing an electrode pattern on the dielectric substrate; providing a magnetic substrate; providing an electrode pattern on the magnetic substrate; arranging the dielectric substrate and the magnetic substrate so that their faces provided with the electrode patterns are facing each other, and so that the electrode patterns are facing each other at a predetermined connection portion, and connecting the electrode pattern of the dielectric substrate to the electrode pattern of the magnetic substrate at the predetermined connection portion.
Consequently, the electrode pattern can be moved near to the dielectric substrate side at a predetermined position, and the electrode pattern at other positions can be moved near to the magnetic substrate, using a conventional flip-chip mounting technique.
Yet another method for manufacturing a nonreciprocal circuit device may comprise the steps of providing a dielectric substrate; providing a film of low dielectric constant, comprising a substance having a lower dielectric constant than the dielectric substrate, on the dielectric substrate; providing an electrode pattern such that a resonator portion is formed at the portion of the dielectric substrate where the film of low dielectric constant is provided, and a transmission line portion is formed at other portions thereof; affixing a magnetic substrate to the dielectric substrate which the electrode pattern has been provided; and providing a magnet for applying a dc magnetic field.
Consequently, a nonreciprocal circuit device having an electrode pattern provided near to the dielectric substrate or the magnetic substrate at a predetermined position can be manufactured in a single process.
Yet another method for manufacturing a nonreciprocal circuit device may comprise the steps of providing a dielectric substrate; providing a magnetic substrate; providing an electrode pattern on top and bottom faces of a substrate of low dielectric constant having a lower dielectric constant than the dielectric substrate; providing a through hole running between the electrode on the top face and the electrode on the bottom face; affixing the dielectric substrate to the magnetic substrate so as to clasp the substrate of low dielectric constant therebetween, and so that the magnetic substrate is on the resonator portion side of the electrode pattern, and the dielectric substrate is on the transmission line portion side of the electrode pattern; and providing a magnet for applying a dc magnetic field.
Consequently, a nonreciprocal circuit device having an electrode pattern provided near to the dielectric substrate or the magnetic substrate at a predetermined position can be easily manufactured by affixing the dielectric substrate to the magnetic substrate, with the substrate provided with the electrodes clasped therebetween.
Yet another method for manufacturing a nonreciprocal circuit device may comprise the steps of providing a dielectric substrate; providing an electrode pattern forming a transmission line portion on the dielectric substrate; providing a magnetic substrate; providing an electrode pattern forming a resonator portion on the magnetic substrate; arranging the dielectric substrate and the magnetic substrate so that their faces provided with the electrode patterns are facing each other, and so that the electrode patterns are facing each other at a predetermined connection portion, connecting the electrode pattern of the dielectric substrate to the electrode pattern of the magnetic substrate at the predetermined connection portion, and providing a magnet for applying a dc magnetic field.
Consequently, the electrode pattern can be moved near to the dielectric substrate side at a predetermined position, and the electrode pattern at other positions can be moved near to the magnetic substrate, using a conventional flip-chip mounting technique.
These and other features and advantages will be understood from the following detailed description of embodiments of the invention, with reference to the drawings, in which like references denote like elements and parts.